Olefin sulfide addition products



Patented Dec. 13, 1949 OLEFIN SULFIDE ADDITION PRODUCTS Harold R. Snyder, Urbana, Ill., and John M. Stewart, Missoula, Mont., assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Original application May 9, 1947,

Serial No. 747,122. Divided and this application July 26, 194 8, Serial No. 40,799

12 Claims.

This invention relates to the production of mono-addition compounds of olefin sulfides and aliphatic mercaptans. More specifically, it relates to a process for the addition of aliphatic mercaptans to olefin sulfides to produce betasubstituted mercaptans, and to the products produced by said process. This application is a division of our co-pending application, Serial No. 747,122, filed May 9, 1947.

Substituted mercaptans of the type produced by the process of this invention are beta mercapto thio-ethers potentially valuable in chemical processes, particularly in the manufacture and processing of synthetic rubber, the-synthesis of sulphur-containing organic chemicals and the like. Previous attempts to produce such compounds by the interaction of an olefin sulfide with a mercaptan met with little success, the product being generally an indefinite mixture of di-, tri-, and higher addition compounds with little if any of the desired mono-addition products being obfide reacts with primary aliphatic mercaptans to form primary beta-substituted mercaptans; cyclohexene sulfide, secondary beta-substituted mercaptans; and isobutylene sulfide, a mixture of the isomeric primary and tertiary beta-substituted mercaptans.

An object of the present invention is to provide a process for the production of beta-substituted mercaptans. Another object is to provide a process for the production of mono-addition compounds of olefin sulfides and aliphatic mercaptans. Still another object of this invention is, to provide beta-substituted mercaptans as new chemical compounds.

New chemical compounds may be prepared by,

the reaction of an olefin sulfide with an aliphatic mercaptan in accordance with the present invention. The olefin sulfides, of which ethylene sulfide is the simplest member, contain a sulfur atom attached to two directly-connectedcarbon atoms Primary, secondary or tertiary beta which may be represented structurally as follows:

wherein the carbon atom may be a part of a ring or of an open chain of greater length. As examples of olefin sulfides suitable for use in the process of the present invention, in addition to ethylene sulfide, the following may be mentioned: propylene sulfide, isobutylene sulfide, normal butylene sulfides, higher alkene sulfides, cyclic olefin sulfides, e. g., cyclopentene sulfide, cyclohexene sulfide, and the like, and substituted olefin sulfides, e. g., phenyl propylene sulfide.

The reaction of olefin sulfides with aliphatic mercaptans proceeds according to the following equation:

where R is an aliphatic radical attached to the SH group of the mercaptans. Primary, second ary, or tertiary mercaptans may be used for car-. rying out the reaction with olefin sulfide in accordance with this invention. Unsaturated mercaptans, e. g., butenyl mercaptan, may be used in the process, as well as the more readily available saturated mercaptans. Primary aliphatic mercaptans are, in general, most reactive. The aliphtic mercaptans containing from 2 to 16 carbon atoms per molecule are preferred. It is evident that numerous new chemical compounds may be'produced by the present process.

In carrying out the reaction, a mixture of the mercaptan and olefin sulfide is used, usually with the mercaptan present in an amount in excess of that theoretically required for the reaction. Generally it is desirable to form a mixture in which the mercaptan is present in an amount approximately twice the theoretical amount or in per cent molar excess. Desirably, but not necessarily, the reaction mixture is agitated during at least a part of the reaction period.

The reaction may be carried out at various temperatures and pressures and for widely different periods of time. While a temperature within the range offrom about 0 'C. to about 250 C. may be employed, preferably the reaction temperature is within the range of from about 20 C. to about 160 C. To increase the rate of reaction, it is often desirable to heat the mixture of reactants to a temperature somewhat above normal room temperature (20 C.) but generally not above the 5 boiling point of the mixture. It will be obvious to one skilled in the art that the lower temperatures require increased reaction times and that a temperature above the decomposition temperature of reactants or products should not be employed. The temperature required for optimum rate of reaction will vary with different starting materials, but a temperature of about 100 C. is generally satisfactory for the process. A number of reaction products of olefin sulfides and-mer 15.

captans have been prepared by heating the reaction mixture to 100 C. by, the use of saturated steam at atmospheric pressure. While thereaction is preferably carried out in liquid phase,

it may, in some instances, be: carried'outin :vapor;

phase if desired. A reaction period of fromabout 1 hour to about 60 hours is suitable for the reaction, but a reaction time of from about 2. to about 24 hours is generally sufiicient and preferably employed. While the pressure may be varied over 5 a rather wide range without appreciably afiecting the rate of reaction, ordinary atmospheric pressure is convenientlyused incarrying out the process of the present invention.

.Catalysts which may beused in the process'oi ,of aboronfluoride addition product suitablev as a .catalyst foroun process. v.The boronfluoridecomplex is prepared by the addition of boronfluoride to the acid. The reaction between the acid and the boron fiuorideis exothermic, and should be Of, the boron .fluopure form. Distillation of the product is preferably carried out at a pressure of about 5 mm. of mercury absolute or less to avoid any tendency toward decomposition at the boiling temperature.

In a specific embodiment of the present invention a primary mercaptan, such as normal hexyl mercaptan, is reacted with an olefin sulfide, such as isobutylene sulfide. The mercaptan is dissolved in ethanol containing sodium as a catalyst in an amount equivalent to about. one mol per cent of the .isobutylene sulfide. :lT-he isobutylene sulfide is then added slowly tothe mixture until a concentration of about per cent on a molar basis of the mercaptan is reached. The mixture is held at. the: boiling-"point under reflux conditions for from about 10 .to about 20 hours after which the ":product'is taken'up'in ether, washed with water,

;and dried. over anhydrous sodium sulfate. The crude product is then distilled under reduced pressure. The reaction proceeds according to the v following"equations to produce a mixture of isomeric; primary and tertiary beta-substituted mercaptans Example I :Annixture fiflIIlHGFiEIfiIDSZ (0.111: mol): otn-butyl mercaptan; andxtwo: drops 0f1boroncfi11oridesether catalyst awasnplacedxin: a1 200=-ml. LLthree-necked flask fittedxwith: six-mechanical; stirren: reflux condenser; and"; droppingi funnel. Thezimixture was z'.-heated".tcr.steam cone: temperature. .(1'003 C.) and 414: grams" (0.05imol)iofiisobutylene sulfide. added dropwise withrstirringf overs a period: 0145 :min-

:utes. "The imixturexwas maintained zati the recarried out under conditionssuch that the temf temperatur' for} t er'wh h i perature does not rise above about 100 C. The boron fluoride-acetic acid addition compound, which containstwo mols of'acetic acid 'per mol of boron fluoride, is conveniently prepared-by bubbling the boron'fluoride through acetic acid. 50

The addition compound formed from equimoleo- ,ular amounts of boron fluoride and diethyl ether is also a, preferredcatalyst, for theprocess.

The. amount of'catalyst employed is variable and maybe within the range .of from about 0.2 asivrimarwand tenfiarynsomers to about5. mol per cent'of the quantity of. olefin sulfideemployed. Catalyst concentrationoi approximately. one mol per cent based on the olefin sulfide have been found to be satisfactory. Larger .quantitiesoi catalyst may be used but show little,""

Iii an advantage.

111 eneral, the process of our invention comprises forming a .mixture of an aliphaticmer- .captan and the catalyst and. heating themixtur e to the reaction temperature after which. the.o1e-

addition of the olefin sulfide to the, mercaptam'lO .the reactiontemperature should be maintained for the remainder of the reaction period. At the end of the reaction period the addition product --may betaken up in ether, washed,driedand dis was cooled and extracted repeatedly with ether.

The combined extracts were washed with sodium carbonate solution an'd-saturatedsodium'chlbride "solutiomdried over 'anhydroustsodium sulfate, and

distilled under a. pressure of two mm.. or mercury. .Theproduct boiled at. a. temperature of 52-'-53 C. under, a .pressure of. 2 mm. andhad. an. index. of refractionof 1.4936.-at- 20 C. a Amperometric analysis showed. the material: to beeazmixture of the ..'n, C4H9SCH2C(CHa).2SH

in the ratio of 72.4' to 27.6.

Example II ,-.A series otreactions were. .carried out in-which isobutylene:sulfide was: reactedY-with various primaryi-mercaptans. :rlnceachainstancei the prepaaration was madesbyz adding 0.10moi oi'l'the mer- "capta'n' to a' solution of"-0.10"gram" of sodium-:in 13 ml. of absolute ethanoL -foliowed'by 0.05 mol tofthe sulfide. Heat was-evolvedirrall'cases; The mixture was then refluxed for 10-20 hours after which'the product was taken up in ether, washed "with water and dried ovenanhydrous sodium sulfate. *The cru'de product was/then distilled tilled-for recovery of the product in substantially "Na-under 'reduced 'pressure; "-The mercaptans used 51; and the products obtained, together with their properties, are tabulated below:

the group consisting of boron fluoride and a boron fluoride complex formed by the addition.

Mercaptan Products 13. P., O. t 3 Eggs? n'amyl n-OsHnSCKJHshCHzSH- 82-8413 mm.). 1.4920 59.7

11-C5H11SCH2C(CH3)2SH 40. a

n-hexyl n-CH aSC(CH3)2CHzSH 93-96 (3 mm.) 1. 4899 56.0

11106113801320 (CHshSH 44.

n-heptyl n-C1H SG(CHa)2CHzSH 109 (4 mm.) 1. 4356 83.3

n-C1H SCHzC (CHQZSH 1. 16.7

2-ethylhexyl CH3(CH CHCH:SC(CHQzCHgSH 119-121(4.5 mm.).. 1.4885 71.9

CHACHghOHOHrSCHzC(OH:)-

n-dodecyl-.- H'C1ZHZSSO(CHH)ZCHHSH 165-1711 (3 mm.) 1.4845 41.4 n-ouflesomc'gomtsn 58.6

Example III of boron fluoride and an oxygen-containing com-- reaction conditions were substantially the same as in Example II. The mercaptans used and the products obtained together with their properties are shown in the following tabulation:

pound of the class consisting of di-ethyl ether and acetic acid, and recovering from the reac-- tion mixture a resulting beta mercapto thio-- ether.

3. A process for the production of a beta mercapto thio-ether from an olefin sulfide and a primary aliphatic mercaptan, which comprises Mercaptan Product B. P., G. 965 n-butyl 109-111 (2.5 mm.)..-. 1. 5234 -SHC4H9 n-amyl 123-126 (3.5 mm.)..-- 1. 5186 n-hexyl -133 (3 mm.). 1. 5135 S11CH n-heptyl 141444 (3 111111.)-.." 1. 5113 S!1C7H15 We claim: admixing a primary aliphatic mercaptan con- 1. The method of producing a beta mercapto 60 taining from 2 to 16 carbon atoms per molecule thio-ether, which comprises reacting one molecular equivalent of an aliphatic mercaptan containing from 2 to 16 carbon atoms per molecule with a molecular equivalent of an olefin sulfide containing from 2 to 9 carbon atoms per molecule in the presence of a catalyst comprising boron fluoride, and recovering from the reaction mixture a resulting beta mercapto thio-ether.

2. The method of producing a, beta mercapto thio-ether, which comprises reacting one molecular equivalent of an aliphatic mercaptan containing from 2 to 16 carbon atoms per molecule with a molecular equivalent of an olefin sulfide containing from 2 to 9 carbon; atomsrper mole with a catalyst selected from the group consisting of boron fluoride and a boron fluoride complex formed by the addition of boron fluoride and an oxygen-containing compound of the class consisting of (ii-ethyl ether and acetic acid in such proportions that the resulting admixture contains from 0.2 to 5 mol per cent of said catalyst based on the quantity of olefin sulfide employed, adding an olefin sulfide containing from 2 to 9 carbon atoms in the molecule to the resulting admixture with continuous agitation at a temperature within the range of from 20 to C. at a rate such that a quantity of said olefin sulfide equivalent; to about 50 per (cent ofethe theoretical,

cule in the presence of a catalyst selected-from: wnuantity requiredi-for'reaction with said mercap- 2 to 16 carbon atoms per molecule with a catalyst selected from the group consisting 'of boron fluoride and a boron fluoride complex formed by the addition of boronfiuoride and an 'oxygencontaining compound of the classconsisting of di-ethyl ether and acetic'acid, adding to the resuiting admixture an olefin sulfide containing from 2 to 9 carbon atoms in the molecule with continuous agitation at a temperature within the range from about 20 to about 160 C., said olefinsulfide being added at a rate such that a quantity equivalent to about 50 per cent of the theoretical quantity required for reaction with said merca-pacid.

tan is added to said mixture over a period of time 5, Theprocess of claim}, wherein said olefin 7. Theprocess of claim 4, wherein said catalyst 'is the" addition producfidfdfie molecular equivalent ofs-boron fiuorlde;and two molecularcequivc-l alents of acetic acid 8. The process of claim 4, wherein said olefin sulfide is iso-butylene sulfide.

9. The process of claim 4, wherein said catalyst is boron fluoride 10-. The 'methodofproducing a beta-substituted mercaptan, which-comprises reacting .an aliphatic mercaptan containing from 2 to 16 carbon atoms in the molecule; with an olefin sulfide containing from 2 to-"'9 carbon atoms in-the molecule, in the presence ofta catalyst comprising boron fluoride, and recovering as a product of the process a beta 'alkyl 'thio-ether mercaptan so produced.

11. The process of claim 10 in which said catalyst is a complex ofboron fluoride with diethyl ether.

12. The process of claim '10 in which said catalyst is a complexof boron -fluoride with acetic macro R. SNYDER. JOHNM. STEWART.

REFERENCES crrsn The following referenceslal' e of record in the file :of this patent:

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